/* hexedit -- Hexadecimal Editor for Binary Files
   Copyright (C) 1998 Pixel (Pascal Rigaux)

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.*/
#include "dhexview.h"

void openFile(void)
{
    struct stat st;

    if (!is_file(fileName)) {
        fprintf(stderr, "%s: %s: Not a file.\n", progName, fileName);
        exit(1);
    }

    /* edited should be cleaned here (assert(edited == NULL)) */
    isReadOnly = true;
    if ((fd = open(fileName, O_RDONLY)) == -1) {
        if (page)
            exitCurses();
        fprintf(stderr, "%s: ", progName);
        perror(fileName);
        exit(1);
    }
    baseName = basename(fileName);
    mark_set = false;
    lastEditedLoc = base = cursor = cursorOffset = 0;

    /* check file size- doesn't work on devices.  I considered implementing a conquer-and-divide algorithm, but it would unpleasant on tape drives and such. */
    if (fstat(fd, &st) != -1 && st.st_size > 0)
        fileSize = st.st_size;
    else {
#ifdef BLKGETSIZE
        unsigned long i;
        if (ioctl(fd, BLKGETSIZE, &i) == 0)
            fileSize = (INT) i *512;
        else
#endif
            fileSize = 0;
    }
    biggestLoc = fileSize;
}

void readFile(void)
{
    typePage *p;
    INT i;

    memset(buffer, 0, page * sizeof(*buffer));

    LSEEK(fd, base);
    nbBytes = read(fd, buffer, page);
    if (nbBytes < 0)
        nbBytes = 0;
    else if (nbBytes && base + nbBytes > biggestLoc)
        biggestLoc = base + nbBytes;
    memset(bufferAttr, A_NORMAL, page * sizeof(*bufferAttr));
    for (p = edited; p; p = p->next) {
        for (i = MAX(base, p->base);
             i < MIN(p->base + p->size, base + page); i++) {
            if (buffer[i - base] != p->vals[i - p->base]) {
                buffer[i - base] = p->vals[i - p->base];
                bufferAttr[i - base] |= MODIFIED;
            }
        }
        if (p->base + p->size > base + nbBytes) {       /* Check for modifications past EOF */
            for (; p->base + p->size > base + nbBytes && nbBytes < page;
                 nbBytes++)
                bufferAttr[nbBytes] |= MODIFIED;
        }
    }
    if (mark_set)
        markSelectedRegion();

}

int findFile(void)
{
    char *p, tmp[BLOCK_SEARCH_SIZE];
    p = lastFindFile ? strdup(lastFindFile) : NULL;
    if (!displayMessageAndGetString("File name: ", &p, tmp, sizeof(tmp)))
        return false;
    if (!is_file(tmp))
        return false;
    FREE(lastFindFile);
    lastFindFile = fileName;
    fileName = p;
    return true;
}


INT getfilesize(void)
{
    return MAX(lastEditedLoc, biggestLoc);
}


/* tryloc:
 *   returns true if loc is an apropriate location to place the cursor
 *   assumes the file won't shrink.
 *   returns true if the cursor is one past EOF to allow appending
 */

int tryloc(INT loc)
{
    char c;
    if (loc < 0)
        return false;
    if (loc <= lastEditedLoc)
        return true;

    if (loc <= biggestLoc)
        return true;

    if (LSEEK_(fd, loc - 1) != -1 &&    /* don't have to worry about loc - 1 < 0 */
        read(fd, &c, 1) == 1) {
        biggestLoc = loc;
        return true;
    }
    return false;
}

int is_file(char *name)
{
    struct stat st;
    return stat(name, &st) != -1 && !S_ISDIR(st.st_mode);
}
